1. Technical Field of the Invention
This disclosure relates generally to a rotating pumping apparatus with a sealing mechanism in which a sealing member made of up a resinous ring and a rubber ring is disposed in a clearance between a pump casing and a shaft extending in the pump casing, and the resinous ring is placed in close contact with the shaft to create a hermetic seal therebetween, and also to a brake system for a vehicle using such a rotating pumping apparatus.
2. Background Art
Japanese Patent First Publication No. 2012-77762 teaches a brake system equipped with a rotating pump (also called a rotary pump). The rotating pump includes a pump casing, a pump drive shaft, and a sealing member. The sealing member consists of a resinous body and a rubber ring and is disposed between the pump drive shaft and the pump casing to minimize leakage of brake fluid through a clearance between the pump drive shaft and the pump casing. Specifically, the resinous body is placed in contact with the outer periphery of the pump drive shaft, while the rubber ring is disposed in contact with the inner wall of the pump casing so as to elastically press the resinous body against the pump drive shaft to create a hermetic seal therebetween.
The resinous body has an end with a cut-out recess. The cut-out recess has a slant wall which extends in axial and radial directions of the resinous body. The pump casing is equipped with a pin inserted into the cut-out recess of the resinous body. The cut-out recess and the pin function as a rotation stopper. When the resinous body is rotated following rotation of the pump drive shaft, it will cause the pin to hit the slant surface of the cut-out recess, thereby stopping the sealing member from rotating following the rotation of the pump drive shaft. Upon hitting of the pin on the slant surface, the slant surface works to convert the torque of the pump drive shaft into force which elastically urges the resinous body into abutment with a stopper wall of the pump casing, thereby stopping the sealing member from moving in the axial direction of the pump drive shaft.
The above described prior art structure, however, encounters the drawback in that when the degree of friction, as developed between the rubber ring and the resinous body, is greater than the above force into which the torque of the pump drive shaft is converted by the hitting of the pin with the slant surface of the resinous body, it will result in a lack in elastically pressing the resinous body against the stopper wall to stop the linear movement of the sealing member.